CVE-2026-92153 in F Prime
Summary
by MITRE • 10/14/2026
F´ (F Prime) is a framework that enables development and deployment of spaceflight and other embedded software applications. Prior to 4.3.0, Svc::FileUplink handling of Fw::FilePacket::StartPacket destination paths FileUplink copies the packet-controlled destinationPath and opens it for writing without canonicalization or confinement to an upload directory. When a peer able to send file-uplink packets supplies an absolute, traversing, or otherwise attacker-selected writable destination path, files can be created or overwritten at attacker-selected writable filesystem locations, affecting integrity and potentially availability. This issue is fixed in version 4.3.0.
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Analysis
by VulDB Data Team • 10/15/2026
The F Prime framework serves as a critical infrastructure for developing and deploying embedded software applications within spaceflight systems and other resource-constrained environments. These systems often rely on robust mechanisms for remote configuration, firmware updates, and data retrieval to maintain operational continuity in isolated or hostile conditions. A significant security weakness was identified in the Svc::FileUplink component prior version 4.3.0 of this framework. This specific service is responsible for managing the transfer of files from a peer entity into the local system storage. The vulnerability stems from an insufficient validation mechanism regarding how destination paths are processed during file upload operations, creating a pathway for unauthorized filesystem manipulation that compromises the integrity and availability of critical system components.
The technical flaw lies in the handling of Fw::FilePacket::StartPacket structures by the FileUplink service. When initiating a file transfer, the component accepts a destination path parameter directly from the peer sending the uplink packet without performing any canonicalization or confinement checks. Canonicalization is a standard security practice that resolves all symbolic links and relative references to their absolute physical paths, ensuring consistency in path interpretation. Confinement involves restricting operations to a specific directory tree to prevent access outside of designated boundaries. In this vulnerable implementation, the service blindly copies the packet-controlled destinationPath string and passes it directly to system calls for opening files for writing. This lack of sanitization allows an attacker who can send file-uplink packets to specify arbitrary absolute paths or path traversal sequences such as ../..
The operational impact of this vulnerability is severe due to its potential to affect both data integrity and system availability. By supplying a writable destination path that points outside the intended upload directory, an attacker can create new files in unexpected locations or overwrite existing critical binaries, configuration files, or logs. In spaceflight applications, overwriting core executables could lead to mission failure or loss of control over spacecraft subsystems. Similarly, corrupting log files might hinder forensic analysis and incident response capabilities after a breach. The ability to write arbitrary data to writable filesystem locations effectively allows for remote code execution if the overwritten file is subsequently executed by privileged processes, thereby escalating privileges from a potentially low-level network service to full system compromise.
This vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory and CWE-436: Interpretation Conflict, which describe flaws where input does not restrict or validate paths correctly leading to unintended access. From an adversarial perspective, this technique corresponds to ATT&CK T1505.003: Server Software Component Download, as it involves the unauthorized placement of files that may be used for further exploitation. The root cause is a failure in implementing secure coding practices regarding external input validation specifically concerning filesystem operations.
Mitigation strategies must focus on strict path validation and confinement. Systems running versions prior to 4.3.0 should upgrade immediately to version 4.3.0 or later, where this issue has been resolved through the implementation of proper canonicalization and directory confinement checks within the Svc::FileUplink component. For environments unable to patch immediately, defensive measures include implementing network-level access controls to restrict who can send file-uplink packets, ensuring that only trusted peers have communication privileges with the F Prime framework. Additionally, deploying host-based intrusion detection systems capable of monitoring for unusual filesystem write operations in sensitive directories can provide early warning indicators of exploitation attempts.